Magnetic, optical and solid-state media
Magnetic: a read/write head magnetises tiny areas of a spinning disk or tape (hard disk drive, magnetic tape). Optical: a laser burns and reads pits and lands on a disc (CD, DVD, Blu-ray disc). Solid-state: charge is held in flash memory cells with no moving parts (solid-state drive, memory stick / pen drive, memory card). Blu-ray is still on the syllabus. Pick a medium by weighing portability, durability and access speed against the job.
Backing vs primary storage, and virtual memory
Backing (secondary) storage is non-volatile (keeps contents with the power off), permanent and gives large capacity at low cost per unit, but is slower than primary memory. Primary storage is what the CPU uses directly: RAM (volatile, data in current use) and ROM (non-volatile, the start-up instructions). Virtual memory is hard disk / SSD space used as if it were extra RAM when real RAM fills; blocks swap to disk, so it is slower.
Backup vs archive, serial vs direct access
A backup is a copy of current, in-use data, taken regularly so the original can be restored if it is lost or damaged. An archive moves old, inactive data onto separate storage to free up space on the main system while keeping it for the record. Serial (sequential) access reads records in order from the start until the wanted one is found — magnetic tape. Direct (random) access jumps straight to the location — disks and solid-state media.
Drawn from real examiner reports.
USB is a port, not a storage device
USB (universal serial bus) is the connection; the storage device is a memory stick / pen drive or a portable solid-state drive. Writing "USB" when asked to name a backing storage device earns no credit, and examiners record it turning up sitting after sitting. Name the device that holds the data, not the socket it plugs into.
Flagged s23 P12 Q12 · w22 P13 Q10
"Characteristic" means a property
A characteristic is a property of the storage — non-volatile, permanent, large capacity. Examiners recorded that the word itself was misunderstood: describing what you do with the storage, or naming a device, does not answer "state a characteristic". The credited answers were non-volatile and permanent. A vague "it stores things" scores zero.
Flagged s23 P12 Q12b
Backing storage ≠ backing up data
Backing (secondary) storage is simply the non-volatile storage that holds programs and data long-term — hard disk drives, solid-state drives, optical discs. Some candidates read the word "backing" and wrote about making backups instead, which is a different idea entirely (a backup is one use of backing storage, not what the term means).
Flagged s23 P12 Q12b
A Blu-ray disc holds LESS than a hard disk
Asked to compare Blu-ray discs with internal hard disks, candidates wrongly assumed the Blu-ray disc held more data. An internal hard disk drive has far the greater capacity; what the Blu-ray disc genuinely offers over it is portability. Get the capacity order right before you try to build any argument on top of it.
Flagged s23 P12 Q12a
Blu-ray is the technology, not the medium
Writing "blu-ray" on its own names the technology. The storage medium is the Blu-ray disc — the disc is the object data is written to and read from. The same discipline applies across this topic: name the thing that holds the data, never the system, the technology or the port associated with it.
Flagged w23 P12 Q8d
The internal SSD vs the memory stick
A solid-state drive can be an integral internal component of a computer, not only a portable device; a flash memory stick / pen drive is always the separate portable one. Candidates confused the two even though the question stem made clear which was meant. Read the stem, then answer about the device it actually names.
Flagged s22 P12 Q6
Cost and capacity score nothing on compares
On device- and media-comparison questions examiners rule cost, storage capacity and battery life "too subjective" and award no credit. So "the pen drive is cheaper" or "the hard disk holds more" is a non-answer even though both are comparatives. Compare instead on durability, portability, access speed or the need for an internet connection.
Flagged w22 P11 Q12 · s22 P11 Q4 · w22 P13 Q10b
"Explain" needs a because
On an explain question "an SSD is smaller" or "quicker" is half an answer and scores nothing. Add the reason: "more portable because it has no moving parts, so it is lighter and survives being knocked".
Compare in matched pairs
Make a like-for-like point on the SAME feature — portability vs portability, durability vs durability, access speed vs access speed — and carry a comparative word ("more shock-resistant than"). Listing unconnected facts about each device is not a comparison.
Use generic device names
Brand names score zero anywhere on the paper — write solid-state drive, memory card, hard disk drive. If a question asks for other portable devices, do not repeat one already named in the stem, and never offer an internal hard disk or a Blu-ray disc as portable.
Convert units before you divide
In "how many files fit" questions convert everything to one unit first — 1 GB = 1024 MB, 1 MB = 1024 KB — then divide the capacity by the file size. Mixing GB with MB, or slipping to 1000 where the question says 1024, is the usual loss.
Full notes, flashcards, Q&A and the topic quiz for every premium subject.
Premium plans are US$8.99/month or US$49.99/year — first month free.
Studying with a parent's blessing? Show them this.
